Article
Materials Science, Multidisciplinary
Ken-ichi Sasaki
Summary: The collective excitation modes of a two-dimensional electron gas in a static external magnetic field were studied. Different modes with distinct characteristics were identified. By calculating the band structures of chain-like structures, it was found that they resemble the miniband structures in semiconductor superlattices. Additionally, the band structures of edge magnetoplasmons were explained using a continuum model.
Article
Materials Science, Multidisciplinary
E. Monch, S. O. Potashin, K. Lindner, I. Yahniuk, L. E. Golub, V. Yu. Kachorovskii, V. V. Bel'kov, R. Huber, K. Watanabe, T. Taniguchi, J. Eroms, D. Weiss, S. D. Ganichev
Summary: We present a study on the conversion of terahertz radiation into a dc current in spatially modulated bilayer graphene, tunable by magnetic field and gate voltage. We observe a sharp cyclotron resonance in the photocurrent and discover two effects caused by electron-electron interaction: the splitting of the resonance due to Coulomb coupling and the suppression of its second harmonic due to interparticle collisions. A theoretical model that fits the experimental data perfectly is developed, suggesting that the ratchet current is generated in the hydrodynamic regime of nonideal electron liquid.
Article
Physics, Multidisciplinary
Songyang Pu, Ajit C. Balram, Mikael Fremling, Andrey Gromov, Zlatko Papic
Summary: In the long-wavelength limit, supersymmetry (SUSY) describes the relationship between the two collective modes of the Moore-Read state in the fractional quantum Hall effect at filling factor v = 5/2. By constructing wave functions and conducting large-scale numerical simulations, we demonstrate the equivalence between SUSY wave functions and previous descriptions of collective modes based on the Girvin-MacDonald-Platzman ansatz, Jack polynomials, and bipartite composite fermions in the long-wavelength limit. Studying the energies of SUSY wave functions, we find that realistic v = 5/2 systems are close to the putative SUSY point, where the two collective modes become degenerate in energy.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Ken K. W. Ma, Kun Yang
Summary: The theory of composite fermion provides a simple and unified picture to understand a vast amount of phenomenology in the quantum Hall regime. Recently, a low-energy noncommutative field theory for bosons at Landau-level filling factor nu = 1 has been formulated, which reduces to the celebrated Halperin-Lee-Read theory in certain limits. In this work, a Bose-Fermi mixture at total filling factor nu = 1 is considered, and the number density and Fermi momentum of composite fermions can be tuned by changing the filling factor of bosons. In the dilute limit, the energy dispersion and effective mass of composite fermions can be calculated exactly, and the approximation of a commutative field theory is justified.
Article
Physics, Multidisciplinary
Yves H. Kwan, Yichen Hu, Steven H. Simon, S. A. Parameswaran
Summary: The study reveals the topological features of neutral particle-hole pair excitations and their impact on the bound states in correlated QAH insulators. This results in the formation of topological exciton bands with robust features. The research also applies these ideas to broken-symmetry spontaneous QAH insulators in magic-angle twisted bilayer graphene with substrate alignment.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Chengyu Wang, A. Gupta, S. K. Singh, Y. J. Chung, L. N. Pfeiffer, K. W. West, K. W. Baldwin, R. Winkler, M. Shayegan
Summary: In this study, a new and unexpected even-denominator FQHS was observed in a high-quality GaAs 2D hole system at filling factor v = 3/4. This FQHS is observed in the lowest Landau level and exhibits non-Abelian characteristics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Ankur Das, Ribhu K. Kaul, Ganpathy Murthy
Summary: Motivated by experiments on graphene in the quantum Hall regime, this study revisits the phase diagram of a single sheet of graphene at charge neutrality and presents the finding of a coexistence region of magnetic and bond orders. This result provides a possible explanation for experimental observations on the quantum Hall effect in graphene.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
I. S. Eid, B. F. Mohamed, Bin Guo
Summary: Using a linearized magnetoquantum hydrodynamic model and Maxwell's equations, this study investigates the effect of electron exchange on the dispersion spectrum of surface magneto-plasmon polaritons (SMPPs) in a perpendicular graphene-plasmonic structure. The researchers also examine the influences of graphene electron density, dielectric constant, and external magnetic field on the dispersion characteristics of graphene surface magneto-plasmon polaritons (GSMPPs) in both classical and quantum regimes. The results show that these influences significantly affect the dynamics of GSMPPs, with a greater impact observed in the classical regime when the electron exchange effect is present. This study demonstrates the crucial role of electron exchange in modulating the dynamic behavior of SMPPs in graphene-based nano-optical and plasmonic devices.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
Haoxin Zhou, Chunli Huang, Nemin Wei, Takashi Taniguchi, Kenji Watanabe, Michael P. Zaletel, Zlatko Papic, Allan H. MacDonald, Andrea F. Young
Summary: At high magnetic fields, monolayer graphene exhibits competing phases. Recent experiments have observed a special quantum Hall state that is related to the underlying isospin order. However, no direct evidence for this transition has been reported. This study measures the transmission of magnons in monolayer graphene and finds that transmission is controlled by density and restored in the antiferromagnetic regime. Additionally, a hidden phase transition between bulk insulating charge density wave and canted antiferromagnetic phase is directly detected.
Article
Physics, Multidisciplinary
I. S. Eid, B. F. Mohamed, Bin Guo
Summary: This study investigates the properties of surface magnetoplasmon polaritons in a graphene-plasmonic structure and reveals that quantum effects significantly alter the properties of these polaritons.
Article
Physics, Multidisciplinary
Anaelle Legros, Shang-Shun Zhang, Xiaojian Bai, Hao Zhang, Zhiling Dun, W. Adam Phelan, Cristian D. Batista, Martin Mourigal, N. P. Armitage
Summary: In this study, a wealth of multimagnon bound states were observed in the strongly anisotropic spin-1 triangular antiferromagnet FeI2 using time-domain terahertz spectroscopy. These unconventional excitations can alter the properties of ordered magnets due to attractive magnon-magnon interactions. By analyzing the energy-magnetic field spectrum using an exact diagonalization method, up to 4- and 6-magnon bound states hybridized with single magnons were detected, providing a unique platform to study decay and renormalization similar to few-body problems found in cold-atom, nuclear, and particle physics.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Eslam Khalaf, Ashvin Vishwanath
Summary: This study predicts that spin polarons, bound states of an electron and a spin flip, can serve as charge carriers in the Chern-ferromagnet phase of twisted bilayer graphene. This exotic type of charge carrier has important implications in topological bands and may have potential experimental applications in materials like twisted bilayer graphene.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Ryan D. McCurdy, Aidan Delgado, Jingwei Jiang, Junmian Zhu, Ethan Chi Ho Wen, Raymond E. Blackwell, Gregory C. Veber, Shenkai Wang, Steven G. Louie, Felix R. Fischer
Summary: Metallic graphenenanoribbons (GNRs) are essential for low-dimensional functional materials technology as 1D interconnects for electronic and quantum information transport. However, the design and assembly of metallic GNRs have been hindered by the structural constraints in on-surface bottom-up synthesis and limited control over the orientation and sequence of asymmetric monomer building blocks during polymerization. In this study, we report the successful synthesis of GNRs with robust metallic states by embedding a symmetric zero-mode superlattice along the backbone.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Stephan Kuerten, Marvin Zanke, Bastian Kubis, Danny van Dyk
Summary: Using dispersive methods, this study examines the B -> γ* form factors in the decay of B- -> l- (ν̅l)l'(-)l'(+). It discusses the ambiguity that arises from separating the full amplitude into a hadronic tensor and a final-state-radiation piece, taking into account nonvanishing lepton masses. The study proposes a decomposition of the hadronic part to obtain four form factors without kinematic singularities, and relates the B -> γ* form factors to known B -> V form factors using dispersion relations. The results are used to determine the branching ratios and forward-backward asymmetries of the B- -> l- (ν̅l)l'(-)l'(+) process.
Article
Physics, Multidisciplinary
Andrew T. Pierce, Yonglong Xie, Seung Hwan Lee, Patrick R. Forrester, Di S. Wei, Kenji Watanabe, Takashi Taniguchi, Bertrand Halperin, Amir Yacoby
Summary: The passage discusses the ferromagnetic phase observed in the quantum Hall effect and the study of related magnon excitations. By measuring the electron compressibility under the influence of magnons, a reduction in the gap of the quantum Hall state is revealed. The analysis suggests injected magnons bind with electrons and holes to form skyrmions, allowing the extraction of free magnon density, magnon chemical potential, and average skyrmion spin.
